The present invention relates generally to connection insulators for dynamoelectric machine stator assemblies and more specifically to methods for fabricating connection insulators for electrically isolating a plurality of electrical connections of the stator assemblies.
As is well known in the art, dynamoelectric machine stator assemblies may often comprise a magnetic core having a bore, axially extending slots, and windings which may comprise a plurality of coils formed by multiple turns of a conductor. The multiple winding turns have side turn portions which are disposed within the axial extending slots and end turn portions which project from the slots and which are disposed about end faces of the core. The windings may be electrically connected to each other and/or to external power conductor leads in various configurations depending on, for example, whether the windings are connected in parallel or in series, the number of windings, etc., with the interconnections being made by any suitable technique such as brazing, soldering, or crimping, to name a few. Connections or connection points resulting from the electrical interconnections are electrically insulated and generally disposed within or about the end turns of the windings.
In Miller application Ser. No. 844,915 filed Oct. 25, 1977, which issued Aug. 5, 1980 as U.S. Pat. No. 4,215,464 assigned to the assignee of the present invention, and the entire disclosure of which is hereby incorporated herein by reference; new and improved stator connection assemblies and methods of making the same are disclosed, among other things. For example, connection insulators are disclosed having a plurality of insulating compartments or holsters for electrically isolating connections or connection points resulting from the electrical connection of windings of a stator assembly to each other and/or to external power conductor leads. The connection insulator is secured to the outer periphery of winding end turns which eliminates cut-through problems caused by embedding connection insulators within winding end turns.
Multipocketed insulators may encounter some cut-through problems even if not embedded within winding end turns of stator assemblies although the problems may occur less frequently. For example, burrs or sharp edges of connection points may damage the insulating material establishing the pockets during insertion of the connections; or high resistance connections may result in elevated temperatures and resultant burn-through problems. Further, problems may be encountered in maintaining the integrity of pockets in that a pocket may be distorted when a connection involving several wires is inserted into the pocket. However, fabrication of connection insulators from a material less susceptible to cut-through, burn-through, and distortion may cause subsequent mounting problems and/or increase fabrication problems. Thus, it would be desirable to develop solutions which would alleviate or minimize these problems without creating mounting or fabrication problems.
Although use of multipocketed connection insulators may produce many benefits such as a reduction in steps required to isolate multiple electrical connections, difficulties in fabricating connection insulators with multiple insulating pockets or compartments may offset many of the benefits derived as a result of their use. For example, fabrication processes for multipocket insulators often require multihandling and manipulation of discrete pieces of material at operating stations where different process steps are performed. The multihandling of pieces of material or materials often constitutes significant portions of the time and the expense involved in the fabrication process.
Accordingly, a general object of the present invention is to provide new and improved methods for fabricating connection insulators.
Another object of the present invention is to provide new and improved methods of fabricating multicompartment connection insulators which minimize fabrication steps and material handling.
Still another object of the present invention is to provide new and improved methods of fabricating multicompartment connection insulators from strips of material of indeterminate length; and which minimize scrap material.
A further object of the present invention is to provide new and improved apparatus and methods for substantially closing at least one insulating compartment of a multicompartment connection insulator.